The prior art already discloses a method of manufacture in which such reinforcements are manufactured directly on the green tire from a continuous thread, by casting the said thread in the manner of a whip, rather than as previously in the form of plies which are incorporated as the tire is built.
The term thread is to be understood in the very broad sense, encompassing a monofilament, a multifilament, a cord or a folded yarn or an equivalent assembly, and irrespective of the textile or metallic material of which the thread is made or the treatment it may undergo, for example a surface treatment to encourage it to bond closely with rubber, or even a rubberizing treatment surrounding the said thread with a layer of rubber to allow it to adhere directly to the support as it is cast.
A device such as this is described in publication EP 248 301. FIG. 1 illustrates the main components that make up this type of apparatus.
The thread 1 is introduced into the device from a feed source (not depicted). The apparatus casts lengths of thread onto a receiving surface which may be formed indifferently either by the crown of a green tire or alternatively by a separate support annulus or alternatively a flat surface.
The said device comprises:                a feed means 11 for feeding the thread 1 from a source of thread,        a rotary guide 2 fixed to a hollow shaft 20 constituting the axis of rotation RR′ of the said guide, so that the outer radial end 21 of the rotary guide is directed substantially radially with respect to the axis of rotation RR′, the said guide 2 receiving the thread 1 that comes from the said feed mean via the central end 25 of the hollow shaft which it enters following a path that coincides with the axis of rotation RR′, the said thread leaving via the said outer radial end 21, the said feed means controlling the linear speed at which the thread advances along the said rotary guide 2,        means for rotating the rotary assembly comprising the hollow shaft and the said rotary guide at a given speed ω,        means 31 for cutting the thread and acting on the thread in such a way as to part off one length of thread for each revolution of the said rotary guide.        
More specifically, the invention is aimed at the thread feed means. This feed means is intended, each time the rotary guide makes one revolution, to deliver to the inlet of the said rotary guide a given quantity of thread that comes from an external source such as, for example, a spool.
The feed means, according to the known prior art, is formed of drive pulleys 11 the axis of rotation of which is perpendicular to the axis of the thread 1. The pulleys are arranged in such a way that the thread is aligned precisely on the axis of rotation RR′ of the rotary assembly as the thread enters the hollow shafts 20. The drive pulleys are rotated by a motor 12 at a controlled speed so as to confer upon the thread a linear feed speed equal to the length of a length of thread each time the rotary guide effects one complete revolution about the axis RR′. The feed means is mounted on a stand that is fixed in relation to the rotary guide, and as a general rule positioned in the immediate vicinity of the inlet 25 of the hollow shaft.
According to this known prior art, the thread, which at the inlet 25 follows a path that coincides with the axis of rotation RR′, passes from the hollow shaft 20 into the rotary guide 2 via a right-angle bend.
The thread is driven towards the outlet 21 under the combined effect of centrifugal force, which has the tendency to extract it, and of the action of the pulleys 11 of the feed means which have the effect of pushing it. Hence, the path of the thread inside the hollow tube and the rotary guide is relatively easy to control when use is being made of threads of a metallic nature which can experience a certain compression without “buckling”. However, it is found that textile threads are substantially more difficult to use inasmuch as the thread has difficulty in negotiating the bend between the hollow shaft and the rotary guide because of the forces of friction against the internal wall of the guide and of the bend. The thread then folds over on itself, blocking the guide and jamming the installation.